Hydraulic control device



Oct. 8, 1940. 'w.- e. B ALDENHOFER HYDRAULIC CONTROL DEVICE 2Sheets-Sheet attorneys Filed May" 22 1939 I Patented Oct. 1w

CONTROL DEVICE William G. Baldenhofer, Springfield, hio, as-

signor to The Thompson Grinder Company,

Springfield, Ohio, a corporation of Ohio Application May 22, 1939,Serial No. 274,900

3 Claims. (Cl. 121-45) Y This invention relates to hydraulic controllingdevices and as shown and described it is especially applicable toinstallation in the fluid pressure systems of hydraulically-operatedmachine 5 tools, the invention being particularly adaptable r to themanual control of the movements of a movable member such as thework-table of a grinding machine.

Referring to prior machine tool designs, it is m practically a universalprocedure to provide arrangements such as-the well-known form of screwand hand wheel mechanism for the movement of these parts. From a veryearly date in machine tool design rotary movement of a hand wheel andcrank has been translated by these screw arrangements into movements ofa member. in

- a desired lineal direction. Thus, it is almost invariably the casethat clock-wise rotation of a hand wheel causes a movement of the partto the go light, and in a similar manner anti-clock-wis rotation of ahand wheel 'producesa movement to the left of the operator. Also, inparts that are to be moved away from or toward the.

operator, or which are to be elevated or low- 5 ered, clock-wiserotation produces movement away from the operator or elevates the partwith reference to vertical movement, and anticlockwise rotation bringsthe part nearer the operator or lowers the movable part, referring 30 tomovement in a verticalv direction.

While power-operated devices for the purpose of feeding the tool intothe work and vice-versa have been in use for a number of years, it isstill customary to resort to manual control for such 35 operation astool setting. As parts became heavier the demand on the physicalstrength and endurance of the operator increased to the extent thatoperator-iatigue became a factor tending to limit the output of amachine.

40 An object of the invention is to provide an improved device of thischaracter, the construction of which will permit the maintenance of asuitable degree of pressure on the fluid motor at all times, not onlywhile the machine is at 45 rest but also during the time the movablepart is in motion. This is brought about by providing that the enteringfluid admitted to theworkin'g side of the fluid motor is always subjectto -exhaust port resistances; that is, no more fluid 0 may cuter than isbeing displaced from the op- .posite side. This places the fluid motorunder a sort of hydraulic lock which is of advantage in preventing amovement of the part such as might be caused by an external force.

55 The advantage obtained by this const ction is that there is provideda control over exhaust fluid flows in comparison with prior hydrauliccircuits which results in the reduction of the extent of any finalmovement made by the movable member after the fluid supply is shut off.By this 8 final movement is meant a movement of theparts after thecontrolling valve (of any previously known type) is closed whichmovement is traceable to a release or reduction of tension in theconduit arrangements, sometimes includ- 10 ing the fluid motor itself.This movement is more noticeable in those hydraulic systems in which acomparatively long resilient piping or: conduit arrangement is employed,since with comparatively high pressure the stressed. condition of theconduit arrangement acts as a spring to return a slight amount of powerwhich causes the final movement mentioned after the controlling valve isclosed. With the present device this final movement is reduced in extentby the simple expedient of controlling the exhaust flow and thus keepingthe conduit arrangement under tension by maintaining pressures thereon.

Other objects and advantages will appear from the accompanying drawings,specification and claims.

In the accompanying drawings:

Fig. 1 is a view partly in elevation and partly in transverse section ofso much of a typical machine as is needed to show the application of theinvention to the machine, the sectional view being taken on the line l-lof Fig. 2.

Fig. 2 is a view partly in elevation and partly in longitudinal sectionon a reduced scale, the sectional portion being taken on 'theline 2-2 ofFig. 1. s

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1 through thedevice itself and may therefore be regarded as a transverse sectionalview. This also applies toseveral following views. 40 Fig. 4 is asectional view on the line 4-4 of] Fig. 1.

Fig. 5 is an enlarged sectional view on the line 5-5 of Fig. 1, showinga companion pair of internal parts in one working position.

Fig. 6 is an enlarged sectional view on the line 6-6 of Fig. 1, showingthe same companion pair in one of its working positions.

Fig. 7 is an enlarged sectional view similar to Fig. 5 showing thecompanion pair of parts in another working position.

Fig. 8 is an enlarged sectional view similar to Figs. 5 and 7 but withthe parts in a still different working position.

Fig. 9 'is an enlarged sectional view similar to Fig. 6 with the partsin a different working position as compared with Fig. 6.

Fig. 10 is an enlarged sectional view similar to Figs. 6 and 9 with theparts in a still different working position.

Fig. 11 is a longitudinal sectional view on the line II-|| of Fig. 7.

Fig. 12 is a fragmentary perspective view with portions broken away ofdetails employed in a modified form of the invention. In general thescale is the same as in Fig. 1.

Fig. 13 is a partial perspective view of a detail employed in themodified form on the same scale as Fig. 12. v

Fig. 14 is a partial view in perspective of a detail that coacts withthe detail. shown in Fig. 13

in the modified form. The scale of this view is also the same as Figs.12 and 13.

Referring to the drawings, a portion of the base is indicated at I. Onthis base I there is mounted for sliding movement from left to right andvice versa a machine element, a portion only maneuvering the work-table2 there is provided a fluid-motor 5 comprising a cylinder 5 secured atone end 5 to the left end of the base I. At the opposite end of thecylinder is the gland'head 6 through which passes the piston rod Ithrough the usual gland 8. On the inner end of the piston rod 1 there isfixed the piston 9, while the outer end I of the piston rod I isattached to a depending bracket I0 secured to the underside of the righthand end of the work-table 2. As seen in Figs, 1 and 2, the longitudinalaxes of the cylinder 5' and piston rod I are parallel to the line ofmotion of the work-table as represented by the V-way 3.

Power for the operation of the work-table under the control of theimproved device is furnished by the pump I2 shown diagrammatically inFig. 2.

The pump 2 takes its suction from the reservoir I3. From'the dischargeside of the pump a conduit |4 leads to the device through an interveningpressure regulating and relief valve I5 and a three-way valve I6, thefunction of which will appear later. From the control device the fluidsupply to the fluid motor 5 branches to provide the conduits I1 and I8leading to the left and right hand ends respectivelyof the fluid motorwith valves I'I' and'I8' interposed in the conduits" and I8 as seen inFig. 2. An exhaust conduit 20 is provided leadingfrom the control deviceto return the exhaust fluid to the storage reservoir l3.

To perform the function of controlling worktable movements in amanner inwhich a rotary crank or hand-wheel is employed, the feed device consistsof two revoluble main parts, the manually rotatable hand or pilot valve2| and the complemental rotary-follow-valve 22. Hereafter in allreferences tothe valves 2| and 22, the terms pilot valve and followvalve, respectively, will be used.

-The pilot valve 2| is manually rotatable in I either direction ofrotation through the medium of a gear train that is set in motion by anyenclosed in the gear casing 26.

means such as by a hand wheel 23. In the present case the gearing isshown only in Fig. l and the description-thereof is limited in detail asany suitable type of gearing may be employed if desired. In practice thetype of work to be performed by the aid of the improved device de-'termines the form and ratio any gearing may take. It should beunderstood also that in some applications satisfactory results areobtainable with no gearing, a direct connection being had with the pilotvalve 2| itself.

-When gearing is used as in the present case it is mainly for thepurpose of providing sensitiveness in work-table movements. For example,it might prove to be difficult with a. directly connected arrangement asmentioned, for the operator to bring about a work-table linear movement,say as smallas .005" because the partial rotation of the hand wheelwould then necessarily also be very small. With the step-down gearingshown the control is more sensitive, since in this case the hand wheelwould be revolved through a. partial rotation, the angle of which may beon the order of ten to fifteen degrees.

Rotary motion of the hand wheel 23 is transmitted to the pilot valve 2|by the gearing shown The gearing is of the form sometimes known asepicyclic and was selected simply because with this forma comparativelylarge ratio is obtainable with few parts, and further it permits thecentral positioning of the hand wheel 23 with respect to the device. I

The hand wheel is secured to a short shaft 23 which in turn is securedin the.central1y disposed bore in a disk-like member 23 rotatablysupported on the inner side of the cover plate of the gear casing 26. Ata suitable distance or radius from the axis of rotation of the disk 23"is fixed a stud carrying a double gear comprising preferably an integralcombination of. two gears, one of which designated as 24" meshes withthe previously mentioned gear .24 fixed to the shaft extension 24 of thepilot valve 2|, and the other, a gear 24a which is meshed with a fourthgear 26' stationarily fixed on the concentrically disposed hollow hub 26of the main body portion of the gear casing 26. It can be seen that theshaft extension 24 extends through the hollow hub 26".

When the hand wheel is rotated the combination gear is caused to revolveor roll around the fixed gear 26' and of course to rotate about its ownaxis of rotation as represented by the stud in the disk 23". The rollingeffect causes a driving action on the part of the gear 24" with respectto its mating gear 24 on the pilot valve extension 24, and since as inthe present case there are two less teeth in the gear 24" as compared tothe gear 24' (the gear 24a and the fixed gear 26" have an equal number)the driven gear 24' is slowly driven in the same direction of rotationas that of the hand wheel 23. In' the present gearing the gear 24" hasthirty-nine teeth, and one rotation of the hand wheel 23 causes apartial rotation of the pilot valve of 3& of a turn, allowing an overallratio of approximately 19.5 turns of the hand wheel to one turn of thepilot valve.

Mention is made later as to how sensitiveness in control is partly aresult of gearing in stepdown ratio and partly a result of the manner inwhich the coacting valve members 2| and 22 are ported for fluid flows.In any event it is usually preferable that the pilot valve 2| is causedaxis of the tubular valve housing 21 is co-axially disposed withreference to the gear casing. The

rearward end of the valve housing 21.is closed with a head 28 secured byscrews. The follow valve 22 is snugly fitted for substantially oil-tightrotation in thebore of the valve housing 21. The follow valve is alsotubular in form and is closed at one end (right hand end) by a head 30secured with screws 3! (see Fig. 12 showing modification of invention).Projecting rearwardly/Irom the head 30 is a stub'shaft 30' securedthereto in any suitable manneras by pinning as shown, the stub shaft 30'passing through a centrally disposed opening in therear head 28 of thevalve housing. A gear 32 is fixed on the projecting rearward end of thestub shaft 30' and meshes with a rack 32' (Figs. 1 and 2) attached tothe under side of the work-table 2 in parallel alignment with thedirection of movement thereof.

The pilot valve 2l is snugly fitted for substantially oil-tight rotationin the centrally disposed bore of the follow valve 22. The pilot valve2i is thus received in a sort of telescopic fit within the follow valve22 while the follow valve 22 is itself also telescopically receivedwithin the central bore of the valve housing 21. j

The coaction of the pilot valve 2| and follow valve 22 is by means offluid admission and exhaust ports in the pilot valve which are rotatedinto or out of registry with passages in the follow valve 22 whereby anobject of the invention is attained, i. e., that of using rotary motionof a hand-wheel or crank in work-table maneuvering.

It will appear, however, that rotating out of registry is not so muchthe result of a positive action on the part of the operator as it is theresult of a mere cessation of hand wheel rotation bythe operator. I l j.Since the fluid motor 5 must receive fluid in alternate ends to eifectwork-table reversals, there is provided in the pilot valve 2|, twospaced apart regions or planes in which alternately interspersedadmission and exhaust ports are located. These regions are located inplanes transversely disposed to the longitudinal axis of rotation of thepilot valve and are represented by the lines on which the sections 5-5and 6-6 are taken. Thus there is a group of admission ports inthe planeat the section line 5-5 and a separate set of admission ports in theplane at the section line 8-6. Both groups are fed from a common sourceof fluid supply and each group controls the fluid flow to a particularend of the fluid motor. Interspersed with these admission ports are.exhaust ports.

Admission ports indicated at 33 in the plane at the section 5-5, Figs,5, 7 and 8, admit on proper registry with certain passages in the followvalve 22 a flow of fluid to the left hand end of the fluid motor 5. Inthe'present instance Jthree admission (and exhaust ports) are providedin each region. The advantage in employing a comparatively large numberof ports creased as the number of admission ports is increased. Theplanes are separated longitudirelationship of these admission ports withpassages in the follow valve 22 is as seen in Figs. 5 and 6. Referringto Fig. 5 it will be seen that each admission port 33 is closed by thesolid wall of the follow valve, the same condition being true withreference to each admission port 34 as seen in Fig. 6 which illustratesthe section at the line 5-6.

When these ports are closed as just described, it indicates thework-table is in a state of rest. It can also be taken to mean that theclosed condition is almost always a result of a previous work-tablemaneuvering.

Each of the threeadmission ports 33 is ec1ui-- distantly spaced fromeach other, and each of the admission ports 34 is similarly spaced forthe purpose of providing hydrostatic balance whereby the rotarymovements of one valve relative to the other are free of any clampingeffect.

The method of supplying fluid to the admission ports is taken up in alater part of the specification. This also applies to the manner inwhich the exhaust fluid is returned to the storage reservoir.

To direct a flow of fluid to an end of the fluid motor 5, for example,the left end, which 22 designated as 36, whereupon fluid flows througheach of the admission ports 33 in substantially equal quantities throughthe passages 36 as shown by the arrows, the passages 36 being alsoequidistantly spaced as are the admission ports 33.

be noticed that there are three other identical passages in thissameregion, it will appear later that these are exhaust passagesinterspersed between the passages'35. I

All of the passages 36 (and these latter mentioned passages) communicatewith a peripheral groove 38 formed in the exterior surface of the followvalve at this plane, 1. e.. the section 5-5 (Fig. 1 also). In alignmentwith this peripheral groove 38 is a threaded opening 39 in the valvehousing 21 into which is threaded an end of the conduit l'l previouslymentioned whereby the fiuidis conducted to the left end of the fluidmotor through'the opened valve ll. The groove 38 is a continuousperipheral groove for the purpose of providing hydrostatic'balance.

Referring now to Fig. 10, the pilot'valve 2| is here shown in positionto direct a flow of fluid to the right hand end of the fluid-motor. Asmight be inferred this position is the result of an anticlock-wiserotation of the pilot valve relative to the follow valve 22. Theadmission ports 34 of the group at the plane at the section 6-6 are nowin partial registry with adjacent passages 31 in the follow valve 22 andas has been described For the three admission ports there. are threeadjacent passages 36, and while it may the passages 31 communicate witha peripheral groove 4| formed in the manner as was described inconnection with the similar groove 38. In the wall of the valve housing21 is a threaded opening 42 in radial alignment with the groove 4| andinto the opening 42. is threaded one end of the previously mentionedconduit I8 whereby fluid is conducted to the right hand end of thefluid-motor'5 through the valve I8 which is now in an opened position.

Inasmuch as any work-table movement ineither direction causes adisplacement of fluid from the end of the fluid motor opposite to thatin which fluid is entering, it follows that provision must be 'made tocarry away such displaced exhaust fluid. This is accomplished byproviding exhaust ports in the pilot valve 2|.

Like the admission ports, the exhaust ports are equidistantly spaced,but in the present instance the exhaust ports are positioned in adifferent phase relation with reference to the admissison ports Thereason for the phase difference is that for convenience in manufacturethe previously described passages in the follow valve 22 designated as36 and 31 in the planes at the section lines 5-5 and 66 respectively arein longitudinal alignment (Fig. 1). Thus for each passage 36, Fig. 7,through which flows are being made, there is in longitudinal alignmenttherewith at the plane of the section 6--6 the similar passages 31, Fig.9, through which fluid is not flowing at the time. Interspersedtherewith, however, is a series of three passages 31 through whichexhaust fluid is flowing into the exhaust ports 43 of the pilot valve,and these passages 31' are in alignment with similar passages 36, Fig. 7again, which like the passages 31' are not passing fluid at the time.The admission ports 33 of the group at the plane of the section 55 areout of phase with the corresponding ad- Referring to Fig. 9 which isacompanion figure to Fig. 7 in the sense that admission ports 33 areshown in registry in Figl 7 with adjacent follow valve passages 36, itwill be seen in Fig. 9 that exhaust ports 43 in the pilot valve 2| arein registry with the passages 31' of the follow valve 22. Thereforewhile fluid is flowing through the ports 33 to the left hand end of thefluid-motor 5 to cause, a work-table movement to the right, the fluiddisplaced from the right hand end ofthe motor 5 is flowing in returnflow throughthe passages 31' as shown by the arrows. In the same wayFig. 8,and Fig. 10- are companion figpilot valve in the plane of thesection at 55.

are in registry with follow valve passages I 36'. Arrows here also showthe direction of flows.

It can be seen by the full and broken line showing of the admissionports 33 and 34 in Fig. 7 that fluid may flow only from the ports 33since the ports 34 are at this time closed by the solid wall of thefollow valve 22. Also, in reference to Fig. 8, where by a partialanti-clockwise rotation of the pilot valve, the ports 33 are at thistime blanked by the followvalve and'a flow is permitted only through theports 34.

Referring to any of the Figures 5 to 10, inclusive, it will appear thatthe ports in the pilot valve are alternately fluid admission and exhaustports. Thus taking Fig. 5 alone, a port 33 is an admission port and isbetween two exhaust ports 44, and vice versa. While the alternatespacing of admission and exhaust ports of each series taken together isnot of equidistant spacing, nor for that matter are the ports alternatedas might be inferred from the appearance of the full and broken lineoutlines in any of the Figures 5, 7 and 8, yet since the follow valvepassages 36, 36, 31 and 31 are all equidistantly spaced, all admissionor exhaust ports of a plane taken separately are equidistantly spacedfrom ports of the same character in the same plane. Therefore a partialrotation of the pilot valve 2i relative to the follow valve 22 insuresthat the correct admission ports are brought into registry while allothers of the same character are blanked, while simultaneously with thisregistry the proper exhaust ports are brought into registry in the sameamount with all other exhaust ports closed.

To provide sensitiveness, by which is meant that comparatively smallpartial rotations of the hand wheel 23 cause practically immediateresponse in work-table movement together with practically immediatereversal-should. the hand wheel be turned in the opposite direction, theadmission ports and exhaust ports of a series are grouped together asbest seen in any of the Figures 6, 9 and 10. These figures being of thesection 6-6 have no broken line showing of ports, thereby confusion isavoided in explaining that a pair of admission and exhausts ports are sogrouped as to come within the confines of two adjacent follow valvepassages 31 and 31, whereby as seen in Fig. 6, a very small angularmovement of the hand wheel changes the flow in the peripheral groove 4|from a pressure flow to an present in the admission ports it isessential that there shall be space between adjacent edges such as theedges 34' and 43' sufliciently ample to prevent a loss of fluid pressuredue to leakage over the exterior surface of the pilot valve; and,secondly, tov provide ample flow capacity, it is desirable to have portsas wide as possible measured peripherally; and, thirdly, for sensitivityin operation, to provide that such edges as the edge 3'4" and 43 (Fig. 6only) are as closely adjacent as is consistently possible to the edges31a of the follow valve passages. It can be seen that there is only acomparatively small space between a port edge 34" and a passage edge31a.

It will be understood that this explanation applies to all pilot valveports and follow valve passages.

While sensitivity is obtainable as just described, the responsiveness asregards work-table movements is due possibly more to ample flow capacitythan to any other one factor. It is clear that a plurality of ports doesnot merely divide the flow that is available but rather doubles ortrebles the opportunity of the flow to 'tion shown in that figure.

another means for insuring ample volume of flow,

that is, theports may be elongated in the longitudinal direction of thepilot valve, with an equivalent elongation of the follow valve passagesin the same manner. One method of forming the ports in the pilot valveis shown in Fig. 11. Inasmuch as theexhaust ports may be identical withadmission ports, the reference character 33 employed in Fig. 11 shouldbe construed as being applicable to all pilot valve exhaust andadmission ports. The ports may be in the nature of a gash such as ismade with a key-way cutter, the cutter being so'disposed that the gashis suitably elongated in the longitudinal direction of the pilotvalve. 1By proper spacing of the exhaust ports these latter are caused toregister in exactly the same amount as is noted for the admission ports.By thus placing a deterenton exhaust flows the quantity that can beadmitted is affected since no more can be allowed to enter than is beingpermitted to escape from the fluid motor. Therefore, the pressure in theexhaust side up to the exhaust port is substantially equal to the inletpressure and the entire hydraulic system leading to and from thehydraulic control device to the fluid motor, including the latter, ismaintained in a state of tension whereby the jumping of the work-tableis prevented.

As before mentioned in connection with Fig. '7 the pilot valvetemporarily assumes the, posi- This means that. whenever the pilot valveis given a partial clockwise rotationto the position as shown in Fig. '1where admission ports 33 are in efiective registry or where by ananti-clock-wise rotation admission tation the ports 33 are permittingfluid flow to the left hand end and by themechanical connectionpreviously referred to consisting of the rack 32 on the table which isin mesh with the gear 32 it will be seen that follow valve rotationimmediately follows work-table movement. Clockwise rotation of thefollow v'alve therefore is made which is the same direction as that ofthe pilot valve. This means that if no further clockwise rotation of thepilot valve is made the follow valve passages, 36 would soon. cut oilall flows through the admission ports 33, whereby all fluid directed tothe left hand end of the fluid-motor would be cut off and work-tablemovement would cease. However, should the pilot valve rotation not bestopped but maintained the follow valve would continue rotation in thesame 'ldirection and at a speed in direct relation to work-table speed.Since this speed is directly proportional to the amount of openingallowed so far as admission of the fluid is concerned the follow valvemust rotate in synchronism with the pilot valve.

If the operator desires to accelerate the movement of the table he willrotate the hand wheel at a more rapid rate which for an instant ismovement of the pilot valve relative to the follow valve resulting in awider opening. This can be compared to a wider opening of an ordinarythrottle valve, but with this difference, that to slow down he merelyreduces the speed at which he rotates the hand wheel and to stop thetable he merely ceases rotation of the hand wheel.

It can be seen that during movement there can be no independentacceleration of work-table movement faster than that allowed by theexhaust opening since any such more rapid movement would result in thedisplacement of more fluid than can escape through the exhaust ports.Also. any such jump of the work-table could temporarily convert thefluid motor into a pump. the suction of which would have to be satisfiedindirectly through any admission ports open at the time.

Fluid from the pump under pressure enters the valvehousing through athreaded opening 45 and passes into a peripheral groove 46 formed in theexterior surface of the follow valve 22 at the transverse planerepresented by the section line 3-3, Figs. l and 3. I

From the groove 46 the fluid passes through a .plurality of radiallydisposed openings 41 in the follow valve into a peripheral groove 48formed in the exterior surface of the pilot valve 4 at the same plane.To carry the fluid to the sevpower passages are equidistantly spaced andparallel to the axis of rotation of the pilot valve and after drillingare permanently plugged at rearward or right end as shown by the dottedline plug 50 (see also Fig. 14). v

Where the power passages pass under the peripheral groove 48 a'shortdrilled opening is made to conduct flow of fluid from the groove 48 intothe power passages 49. These short openings are indicated at 51 (Figs. 1and 3). The fluid passes from the power passages 49 to the admissionports 33 and 34 by means of short drilled openings 52 and 53, theopenings 52 being those that are to be found supplying those ports inthe plane of the section 5-5 (see Fig.

5) while the drilled openings 53 are those to be found at the plane ofthe section 63 (see Fig. 6). In this manner one power passage suppliestwo admission ports as is best seen in Fig. 5 where the openings areshown in full andbroken lines.

The exhaust passages are formed in substantially identical manner.Referring to Fig. 5, three longitudinally aligned exhaust passages 54are provided in the main body of the pilot valve in interspersedrelation with the power passages 49. These exhaust passages 54 aredrilled openings and are plugged at the rear end in the same manner aswas described for the power passages 48. The exhaust passagescommunicate with the exhaust ports 44 of the pilot valve in the samemanner as the power passages, there being for each exhaust port in thegroup atthe section 5-5 a short drilled opening 55 and for each exhaustport 43 in t roup at the section 6.-6 a similar short d'ril? opening 56.In this man,- ner one exhaust passage 54 accommodates two exhaust ports43 and 44.

In the pilot valve at the plane of the section .4--4 there is provided aperipheral-groove 51 at posed openings 59 in the follow valve 22 to aperipheral groove 69 formed in the exterior surface of the follow valvein the same manner as wasdescribed in connection with groove 46. Therelation of the pressure groove 46 and exhaust groovefill at thesections 3-3 and 44 respectively and the previously described grooves 38and ll at the sections 55 and 6-6 respectively is best seen in Fig; 1 inwhich view it is seen that all of these grooves are spaced apart adistance sufliciently great to avoid leakage from one groove to anotheror to the'exterior of the device. From the exhaust fluid groove 60 thefluid is conducted to the storage reservoir l3 by means of the conduit20, one end of which is threaded in the exterlor wall surface of thevalve housing 2'! in radial alignment with the exhaust fluid groove 60at the threaded opening 60'.

Modified form -mergency being occasioned for example by a pump or, motorfailure.

For such applications, the device may take on a slightly altered form,one such being'shown herein as a modification. In the foregoingspecification, the description covered the design as shown in Figs. 1 to11, inclusive, in which there was no connectionbetween the valving parts2| and 22 other than the telescopic envelopment oi the hand valve by thefollow valve. Each valve could be rotated independently of the other.

The advantage of this form of construction is that when the work-tableis moved as by power supplied through any of the conventional hydraulicautomatic reciprocating systems, the hand wheel will not rotate inresponse to Worktable reciprocations. The follow valve is the onlyrotating member during such time, the inertia of the hand wheel usuallybeing sufficient to prevent rotation of the pilot valve 2|.

The difference between the form just described and the modified formconsists in the provision of a plurality of equally spaced, coaxiallydisposed lugs 6| preferably integrally attached to the rearward end ofthe pilot valve 2| of the modification (right hand end, Fig. 14) in suchposition as to coact, as a form of jaw clutch, with an equivalent numberof equally spaced lugs 62 projecting forwardly from the forward side(left side, Fig. 1) of the head 30' corresponding to the head 30 of thefollow valve 22 of the first form.

It is preferable that the number of thelugs is equal to the number ofadmission ports in any one group. That is, since in the devicepreviously described, three admission ports are employed,- three lugseach are provided in the-plurality oi lugs on the rear end of the pilotvalve and adjacent forward side of the follow valve head.

The disposition of the lugs on the pilot valve as regards angularrelationship with the follow valve of the modification is such that whenall admission and exhaust ports are out of registry (see Figs. 5 and 6as an illustration) a lug 8| on the pilot valve is midway between twolugs 62 on the follow valve (see Fig. 12)

There is thus provided a clutching arrange- 'ment connecting the pilotand follow valves of the modification but it should be made clear that acertain amount of angular float 'between one valve and the other isdesirable. This float, or

back-lash is obtained by so proportioning the lugs- 2,21e,soo

6| as to not entirely fill the spaces between coacting lugs 62 wherebyin the normal control of the machine under hydraulic pressure, the floatrepresented as the two angles Y and Y, Fig. 12, does not interfere wlthobtaining registry of ports when the hand valve is given a partialrotation in 'either direction. Beyond full registry a lug may actuallycome in contact with an adjacent coacting lug, but it is not likely thatthis will occur, since it is evident that even a partial registry willcause work-table movement, and by the mechanical connection of the rackand gear, such movement will carry a coacting lug 62 of the modifiedfollow valve away from the lug 6| on the modified pilot valve 22.

For emergency movement when there is no pressure in the system theoperator rotates the hand wheel, thereby taking up the float on one sideand the manual power of the operator is then transmitted through thelugs and rack-andgear to move the work-table. Inasmuch as taking up thefloat puts all ports in registry, it is,

clear that work-table movement during emergency periods is not resistedby fluid displaced from the end of the fluid-motor toward which thepiston thereof is moving, since such displaced fluid will find exhaustports leading to atmosphere opened to it. Since the fluid motor isacting as a pump during the emergency periods, the

other end of the fluid motor must be bled, since movement becomes asuction stroke. This bleeding is easily done by opening a pet-cock, hereshown at 63, Fig, 2.

With the modified construction it is evident that, acting as the solemeans of moving the work-table, the device is effective both when giventhe aid of hydraulic pressure in controlling table movements and also inthe emergency periods. However, if at some time automatic power orhydraulic table reciprocation is resorted to, the rotation of the handwheel might be objectionable, to overcome which any of a number ofexpedients are available, a simple one being to remove the gear 32 fromthe machine by first removing the nut 32".

In the assembly of the first form described it is not necessary to useany precautions in regard to placing the pilot valve in any particularrelation with reference to the follow valve. While either may rotateindependently of the other at a time when there is no pressure in thehydraulic system, yet at the instant that pressure is supplied thedevice automatically assumes a closed position if the pilot valve is ina state of rest.

This is explained in this way: Should any admission port be opened atatime when the hydraulic system is charged with fluid under pressure asby starting the pump the work-table will make a slight movement in onedirection or the other to immediately cut off the fluid that caused themovement and the device is then ready to control all subsequentmovements ineither direction of movement by the rotation of the handwheel in the desired direction. This explanation is applicable also tothe device shown as a modifled form.

When a device constructed according to the first form or to the modifiedform is employed as an adjunct in an existing hydraulic system of any ofthe well known types of automatic forms, not shown in the presentapplication, the elements that are common to such systems are thefluid-motor 5 and portions of the conduits l1 and I8. When the device isoperating under an automatic system, in which the work-holder l isreciprocated automatically by fluid. under the control of a work-holderoperated reversing I8" and to avoid any loss of pressure through thehand control devices it is advisable to isolate the hand controlhydraulic system by closing the valves l1 and I8 previously referred to.

In each form drains are provided at the front 10 and rear ends of thepilot and follow valves leading to atmosphere to prevent binding ofvalves. Such drains are indicated at 64 and 65, Fig. 1.

Having thus described my invention, I claim: 1; In a machine of thecharacter described, a movable member, a fluid motor for operating saidmember including a cylinder and piston, a hand-operated rotarycylindrical valve having a pluralityof sets of ports located in onetrans- 2 verse plane and also a plurality of sets of ports located inanother transverse plane, the ports of each set being two in number andspaced apart in a circumferential direction, one of the ports of eachset being an exhaust port and the other one a supply port, the ports ofeach set in one transverse plane being arranged reverselycircumferentially with regard to supply and exhaust to the ports of eachset in the other trans verse plane, a rotary motor-operated valvejournaled on said hand-operated valve and operatively connected withsaid motor, said motor operated valve having an annular channel for thesets of ports which are located in one transverse plane and anotherannular channel for the sets of ports which are located in the othertransverse plane, said channels communicating respectivelywith thecylinder of said motor on opposite sides of the piston thereof, saidmotoroperated valve having two ports for each set of 40 ports in saidhand-operated valve communicating with said channels, each set of supplyand exhaust ports in said hand-operated valve when the motor is at restbeing between two of the ports of the motor-operated valve so as to be45 closed by thewall of said motor-operated valve but being closelypositioned respectively to said last-mentionel ports, whereby when saidhandoperated valve is slightly rotated the supply ports located in onetransverse plane therein. 50 will be opened and the exhaust portslocated in theother transverse plane therein will be opened to admit andexhaust fluid to and from said motor and when said motor-operated valveis rotated all ports in said hand-operated valve 55 therein will bequickly brought in registry with the wall of said motor-operated valvebetween the'ports therein to prevent exhaust from and supply to themotor cylinder and thereby arrest further movement of its piston byproviding a 60 fluid lock for said piston.

2. In a machine of the character described, a movable member, a fluidmotor for operating said member including a cylinder and piston, ahandoperated rotary cylindrical valve having a-plurality of sets ofports located in one transverse plane and also a plurality of sets ofports located in another transverse plane, the ports of each set beingtwo in number spaced apart in a circumferential direction, one of theports of each 70 set being an exhaust and the other one a supply port,the ports of each set in one transverse plane being arranged reverselycircumferentially with regard to supply and exhaust to the ports of eachset in the other transverse plane, said hand-op- 75 ,erated valve havinga plurality of longitudinally extending interior supply passages for allthe supply ports and also a plurality of longitudinally extendinginterior passages for all the exhaust ports, a-rotary motor-operatedvalve journaled on said hand-operated-valve and operatively' connectedwith said motor, said motoroperated valve having an annular channel forthe sets of ports which are located in one transverse plane and anotherannular channel for said sets of ports which are located in the othertransverse plane, said channels communicating respectively with thecylinder of said motor. on opposite sides of the piston thereof, saidmotoroperated valve having two ports for each set of supply and exhaustports in said hand-operated 1 valve communicating with said channels,'each set of supply and exhaust ports in said hand-operated valve whenthe motor is at rest being between two of the ports of themotor-operated valve so as to be closed by the wall of saidmotoroperated valve but being closely positioned re spectively to saidlast-mentioned ports, said motor-operated valve also having an annularfluid supply channel in communication with said 1 interior passages ofsaid hand-operated valve and also having an annular exhaust channel incommunication with the interior exhaust passages of said hand-operatedvalve, whereby when said hand-operated valve is slightly rotated thesupply ports thereof located in one transverse plane therein will beopened to supply fluid from said interior supply passages and theexhaust ports located in the other transverse plane therein will beopened to the exhaust passages in said hand-operated valve to admit andexhaust fluid to and from said motor and when said motoroperated valveis rotated all ports of said handoperated valve will be quickly broughtin registry with the wall of said motor-operated valve to arrest thepiston of said motor by providing a 40 fluid lock for said piston.

3. In a machine "of the character described, a movable member, a fluidmotor for operating said member including a cylinder and piston, ahand-operated rotary cylindrical valve having a plurality of supplyports and a plurality of exhaust ports located in one transverse planeand also a plurality of supply and exhaust ports located in anothertransverse plane; the supply and exhaust ports in each transverse planebeing alternately arranged and equal in number, the ports in onetransverse plane being reversely ar-' ranged to the ports in anothertransverse plane with regard to supply and exhaust, a rotarymotor-operated valve Journaled on said handoperated valve andoperatively connected with said motor, said motor-operated valve havingan annular channel corresponding to the ports of said hand-operatedvalve which are located in one transverse plane and another'annularchannel corresponding to the ports of said handoperated valve which arelocated in the other transverse plane,- said channels communicatingrespectively with the cylinder of said member on opposite sides of thepiston thereof, said motor- 85 operated valve having a plurality ofalternately arranged supply and exhaust ports to cooperate with theports of said hand-operated valve which are located in one transverseplane therein and also a plurality of alternately arranged supply andexhaust ports to cooperate with the ports of said hand-operated valvewhich are located in the other transverse plane thereof, the ports ofsaid motor-operated valve leading to the said 'channels, the ports insaid hand-operated valve to the corresponding supply and exhaust portsof said motor-operated valve but entirely closed by the wall of saidmotor-operated valve, whereby when said hand-operated valve is slightlyrotated the supply ports located in one transverse plane therein will beopened and the exhaust ports located in the other transverse planethereof will be opened to admit and exhaust fluid to and from when themotor is at rest being closely positioned said motor and when saidmotor-operated valve is rotated all ports in said hand-operated valvewill be quickly brought in registry with the wall of said motor-operatedvalve to prevent exhaust and supply to the motor cylinder and therebyarrest further movement of its piston by provid ing a fluid lock forsaid piston.

WILLIAM G. BALDENHOFER.

